#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
using namespace std;
string s1, s2;
int main()
{
	cin >> s1 >> s2;
	int n = s1.size(), m = s2.size();
	vector<vector<int>> dp(n + 1, vector<int>(m + 1));
	for (int i = 0;i <= n;i++) dp[i][0] = i;
	for (int i = 0;i <= m;i++) dp[0][i] = i;
	for (int i = 1;i <= n;i++)
	{
		for (int j = 1;j <= m;j++)
		{
			dp[i][j] = min(dp[i - 1][j - 1], min(dp[i - 1][j], dp[i][j - 1])) + 1;
			if (s1[i - 1] == s2[j - 1])
			{
				dp[i][j] = dp[i - 1][j - 1];
			}
		}
	}
	cout << dp[n][m];
}